Simultaneous LC/ESI‐MS Separation Method for the Enantioseparation of Some New Anticonvulsant Drugs

A sensitive and specific method for the simultaneous determination of the enantiomeric purity of 2,6‐dimethylphenoxyacetyl derivatives as trans or cis racemic and enantiomeric forms with 2‐ or 4‐aminocyclohexanol moiety ( 1 , 2 , 3 , 6 ) and their amine analogs ( 8 , 9 ) was developed. The compounds studied are known for their anticonvulsant activity and the most interesting pharmacological results were those for (±)‐ trans ‐2‐(2,6‐dimethylphenoxy)‐ N ‐(2‐hydroxycyclohexyl)acetamide ( 1 ) as well as (±)‐trans‐2‐[(2,6‐dimethylphenoxy)ethyl]aminocyclohexanol ( 8 ). The analytical method for determining the enantiomeric purity of the compounds studied is based on direct separation of the analytes using a chiral stationary phase (Chiralpak AS column). The mass spectrometric analysis was done on a coupled liquid chromatograph–mass spectrometer system with an electrospray ionization source (LC/ESI‐MS). For the compounds 1 , 8 , and 9 , the method allows an excellent separation of enantiomers, with a resolution higher than 3.2, and a tailing factor of less than 1.67 with a final enantiomer purity better than 97.5%. Chirality 26:144–149, 2014 . © 2014 Wiley Periodicals, Inc.